Evan Spiegel confirmed a tool the app developed to help users find friends was hijacked by hackers. Credit: NBC News

The creator of the photo-sharing app Snapchat has confirmed that a known security flaw was responsible for a hacking that saw more than 4.6 million users' names and phone numbers posted online.

Snapchat received warnings about the flaw in the app's Find Friends service months ago but played down the threat and ignored fresh warnings from a security firm days before the app was spectacularly breached on New Year's Eve.

Evan Spiegel, the app's 23-year-old CEO and co-founder, confirmed to NBC Today the Find Friends function had been "abused" and said he was "outraged" over the hacking.

"At the time we thought we had done enough," he said. "But I think in a business like this ... that is moving so quickly if you spend your time looking backwards you're just going to kill yourself."

Snapchat has since released an updated version of the app which it believes will thwart future hacking attempts.

Snapchat allows users to annotate phone pictures and send them to friends for a limited time.

The founder of increasingly popular photo-sharing app Snapchat has turned down a $3bn (£1.87bn) takeover offer from Facebook, according to a report in the Wall Street Journal.

The smartphone app, co-founded by American Evan Spiegel for a project at Stanford University, allows millions of users - predominantly teenagers - to share photographs which destroy themselves after a few seconds.

Spiegel is hoping that Snapchat, which currently has no charges or advertisements, will be valued at more than $4bn when he considers acquisition offers next year, the report said.